The subject matter disclosed herein relates to a scanner for optically scanning an object and in particular to a scanner that utilizes an uncoded structured light pattern.
Scanners are devices that use noncontact optical techniques to obtain three-dimensional coordinate data of a surface of an object. The scanner typically includes a projector that projects light patterns on the surface. The position of the projector is determined by means of a projected, encoded pattern. Two (or more) cameras, the relative positions and alignment of which are known or are determined, can record images of the surface with a further, uncoded pattern. The three-dimensional coordinates (of the points of the pattern) can be determined by means of mathematical methods which are known per se, such as epipolar geometry.
From the games sector, scanners are known as tracking devices, in which a projector projects an encoded light pattern onto the target to be pursued, such as the user who is playing, in order to then record this encoded light pattern with a camera and to determine the coordinates of the user.
Systems have also been developed for scanning a scene, including distance measuring. The system, in its simplest form, comprises a camera unit with two cameras, optionally with filters, for the stereoscopic registration of a target area. An illumination unit is provided for generating an encoded pattern in the target area, such as by means of a diffractive optical element. This system also includes a synchronizing unit, which synchronizes the illumination unit and camera unit. Camera unit and illumination unit can be set up in selectable relative positions. Optionally, also two camera units or two illumination units can be used.
Accordingly, while existing scanners are suitable for their intended purposes, the need for improvement remains, particularly in providing a scanner that may acquire coordinate data using an uncoded light pattern while being moved.